GIS LANDSLIDES ANALYSIS ii

GIS LANDSLIDES ANALYSIS ii

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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. M.Sc. GIS Program – GEOG 587 class Presented by: Edmundo M. Zevallos April 3rd. 2011
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA.  A Landslide is a Mass movements under influences of gravity.  Occurs as a result of diverse disturbing and destabilizing Introduction processes, for example of climatic or anthropological origin.  The stability of slopes is determined by the geometry of surfaces and slip-horizons. p In regard to spatial landslide analysis, GIS is an important tool to carry out data input, handling, visualization, combination, query, analysis. Ability of the GIS to incorporate the spatially varying data of Hypothesis: ground elevation, soil properties, slope, etc. in the engineering analysis of the slope stability.
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  GIS LANDSLIDES ANALYSIS USC MARINE CAMPUS-TWO HARBORS Roadway between USC Wrigley Institute and Two Harbors ROADWAY Catalina Island, CA. • An analysis of landslide in an specific area of the Catalina Island. • Study Area located in the north west part (section, third) of the island. (section island • In the East-West existing roadway between the USC Wrigley Institute facility and the town of Two Harbors. Research following a spatially-distributed data with a geo-reference to real world. USC Wrigley Institute Existing Roadway Area of y Analysis Two Harbors
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA.  Raster-based GIS was applied in order to analyze the spatial distribution of landslides. landslides  Parameters established in a map: 1.- slope 2.- Geology 3.- Geomorphology 4.- drainage/scour network 5.- Road network Abstract  Four possible landslides spot were inventoried in the study.  Followed by a field work inventory in the North East side of the existing roadway.  Three types of landslides were identified in the study area 1.- scour 2.- rock falls 3.- flows  The landslides are distributed: 1.- 1 on a wide range of slope (15% t 50%) gradient ( f 1) id f l to di t (ref.1) 2.- Two constant geological (ref 2) setting: - Catalina Schist - Volcanic.  This paper will demonstrates the ability of the GIS to incorporate the spatially varying data of: - ground elevation, soil properties, etc. p y y g g , p p , in the engineering analysis of the slope stability.
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. The management of spatial-data is pivotal for this analysis, due: 1. - The unique capability of GIS: to work To capture To store GIS and Landslide Manage the data analysis 2. - The handle of data referenced: by vast spatial Or O geographic coordinates hi di t 3. - Its ability to incorporate appropriate engineering models In the case of the landslide analysis in here, this analysis demands: 1. - Collection of data, 2. - Storage of data 3. 3 - Use of the data for the analysis handled in the GIS environment.
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA.
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. GPS device Reported Number of Description accuracy points taken of points Nomad 5 mt 5 points Drainage (Trimble) Structures and Collection Possible Slide of data land location 630 point GPS devices were GPS Setup to used and their logging results different interval every accuracy. 5 seconds 2,120 points GPS setup to logging interval every 1 meter Geo XH 45 cm 18 points ( (Trimble) )
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. Storage of data and processing ArcMap Layers: ArcMap storage of Data and analysis g y spatially-distributed data and geo-reference to real world. Critical area along road Typical Drainage structure + Typical possible Landslide spot
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. GPS Pathfinder Office Creation of Data Dictionary editor Data Collector device ArcMap storage of Data and spatial analysis Storage of data and processing (cont.) Thickness Sratigraphy thickness Slope 4,521 polygons US Geological Survey Metadata of Catalina Island
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. Formulation of Typical landslide analysis F l ti f T i l l d lid l i  A slope stability analysis combined with risk analyses is proposed to carry out.  The area under investigation is geoprocessed in ArcMap, and marked with more than 4,000 point elevations. elevations  It could observe that the hill is sloping downward towards northwest.  The slide has occurred at the upper regions.  Various man-made features are also present, like roads and only three drainage structures, a stream f lli in the d t falling i th downslope. l
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. Formulation of Typical landslide analysis (cont.)  The steps involved in the landslide hazard it generates a mapping given as flow chart.  The formulation of the work is described.  The methodologygy proposed would be able to develop the hazard map, and perform decision analysis
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. Colored Contours Triangles Triangles DTM surfaces Digital Terrain Model Plan View of Existing Road Profile of Existing Road
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. Conclusions 1) I studied the distribution / characterization of landslides in the study area through: - Photointerpretation - Geomorphologic survey 2) This area of study is characterized by two stratigraphic-structural units: - Mostly Miocene volcanic rocks - Tertiary subvolcanic rocks 3) This research shows that in the area of the analysis there are two types of landslides: - slow earth flow their landslide masses are quite small - rock f ll  occur i limestone formations k falls in li t f ti 4) Morphometric characteristics, play an important role in landsliding processes. 5) Can be determined through the analysis of the digital terrain model.
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. Conclusions (cont.) 6) The application of this method would be useful to locate potential unstable areas, and so to predict the occurrence of future landslides. 7) Since the slides has occurred at the upper regions and hence short-term remediation will be an immediate solution in the form of relief wells. 8) The analysis using: - Hydrologic models could be incorporated in the Arc View - Stability models 9) GIS-based techniques are the best approach to the study of landslide susceptibility because they allow the management of several themes concerning tibilit b th ll th t f l th i instability factors. 10) Geographic Information Systems (GIS) is being exploited widely in many engineering problems which involves spatial data management problems, management.
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. Thank you for your attention Any questions?
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  GIS LANDSLIDES ANALYSIS Roadway between USC Wrigley Institute and Two Harbors Catalina Island, CA. References  Soil Survey of Catalina Island, California. USDA (2008)  USGS - Soils data for the Conterminous United States Derived from the NRCS State Soil Geographic (STATSGO) Data Base. (2001) D t B  Landslide analysis in Geographic Information Systems, G.L. Babu (1998)  Soils data for the Conterminous United States Derived from the NRCS State Soil Geographic (STATSGO) Data Base. (1995) USGS.